Lipids, characterized as oils, greases, fats or long-chain fatty acids are an important organic component of municipal wastewater, their removal being the main concern in wastewater treatment. This paper reports an application of the comprehensive GC×GC/qMS for the evaluation of the lipids removal mechanism in different wastewater treatment plants in order to assess the role of different physical and biological processes over the removal mechanism. For this purpose, the content and fats profile in wastewater were analyzed and calculated. For the separation of the fatty acid methyl esters (FAMEs) enclosed on the fats, two combinations of the capillary columns coated with non-polar/polar and polar/non-polar phases were applied. The validated proposed GC×GC/qMS method presented satisfactory results in terms of repeatability (coefficient of variation lower than 15%), linearity (ranging from 0.5 to 10 μg mL−1), limit of detection (LOD) and limit of quantification (LOQ). In order to increase the consistency of the results, statistical analysis regarding the composition of the fats in both influent and effluent were performed. The results of performed experiments showed that, in the wastewater plant which contains only a physical trap, the removal mechanism is based on the adsorption of fats onto particulate matter, while in the wastewater plants which include a biological trap, the removal mechanism combines the adsorption of fats on the particulate matter in the physical trap with the biodegradation of fats with bacterial activated sludge in the biological trap. As a result, the composition of fats during the biological treatment is modified due to the β-oxidation and other microbial bioconversion processes which through an aerobic biodegradation process destroys the mono- and poly-unsaturated fatty acids and promotes the accumulation of saturated long chain fatty acids.
9 January 2020 in Environmental Science and Pollution Research
Glyphosate is a widely used herbicide, and it is an important environmental pollutant that can have adverse effects on human health. Therefore, remediation and reclamation of contaminated streams and aqueous environments polluted by glyphosate is currently a worldwide priority. Here, we show that the heterogeneous nZVI–Fenton process (nZVI + H2O2; nZVI: nanoscale zero-valent iron) can achieve the effective removal of glyphosate under different operational conditions. Removal of glyphosate can also take place in the presence of excess nZVI, without H2O2, but the high amount of nZVI needed to remove glyphosate from water matrices on its own would make the process very costly. Glyphosate removal via nZVI–-Fenton was investigated in the pH range of 3–6, with different H2O2 concentrations and nZVI loadings. We observed significant removal of glyphosate at pH values of 3 and 4; however, due to a loss in efficiency of Fenton systems with increasing pH values, glyphosate removal was no longer effective at pH values of 5 or 6. Glyphosate removal also occurred at pH values of 3 and 4 in tap water, despite the occurrence of several potentially interfering inorganic ions. Relatively low reagent costs, a limited increase in water conductivity (mostly due to pH adjustments before and after treatment), and low iron leaching make nZVI–Fenton treatment at pH 4 a promising technique for eliminating glyphosate from environmental aqueous matrices.
This research aims to determine five steroids and four non-steroidal anti-inflammatory drugs in milk and egg samples collected from rural Roma communities in Transylvania, Romania. Target compounds were extracted from selected matrices by protein precipitation, followed by extract purification by dispersive liquid–liquid microextraction based on solidification of floating organic droplets. The extraction procedure was optimized using a 24 full factorial experimental design. Good enrichment factors (87.64–122.07 milk; 26.97–38.72 eggs), extraction recovery (74.49–103.76% milk; 75.64–108.60% eggs), and clean-up of the sample were obtained. The method detection limits were 0.74–1.77 µg/L for milk and 2.39–6.02 µg/kg for eggs, while the method quantification limits were 2.29–5.46 µg/L for milk and 7.38–18.65 µg/kg for eggs. The steroid concentration in milk samples was <MDL up to 4.30 µg/L, decreasing from 17α-ethinyl estradiol, 17β-estradiol, and estrone to estriol. The NSAID concentration was <MDL up to 3.41 µg/L, decreasing from ibuprofen, diclofenac, and ketoprofen to naproxen. The steroid concentration in the egg samples was <MDL to 2.79 µg/kg, with all steroids detected, while the concentration of NSAIDs was <MDL to 2.28 µg/kg, with only ibuprofen, ketoprofen, and naproxen detected. The developed protocol was successfully applied to the analysis of target compounds in real milk and egg samples.
This paper aims to assess the pollution by determining the sources of persistent organic pollutants (POPs) in 22 rural Roma communities in Transylvania in order to assess the human health risk associated with this exposure. For this, 16 polycyclic aromatic hydrocarbons (PAHs), 20 organochlorine pesticides (OCPs) and 12 polychlorinated biphenyls (PCBs) were determined in 22 soil samples collected from selected areas by gas chromatography coupled with mass spectrometry for PAHs and with electron capture detector for all halogenated compounds. Target compounds were isolated from soil by ultrasound-assisted extraction. We found that POP concentrations in soil ranged from 4.86 to 451.85 ng/g dw for PAHs, from 25.62 to 139.30 ng/g dw for OCPs, and from 0.22 to 49.12 ng/g dw for PCBs. The diagnostic ratios ƩLMW/ƩHMW, ANT/(ANT + PHE), and FLT/(FLT + PYR) strongly suggest a pyrogenic model of PAHs, such as biomass, coal, and petroleum combustion, while the isomer ratios ƩDDT/ƩHCH, α-HCH/γ-HCH and (DDE + DDD)/ƩDDT suggest that OCP residues originate from their ancient uses. Non-carcinogenic (HI) and carcinogenic (CR) risks of these organic compounds present in the soil through non-dietary pathways were in the very low-risk category (ranging from 10−8 to 10−4), indicating an absence of these risks from the investigated POPs in the studied area.